qa of hydroacoustic instruments · why do we care about qa? many procedures exist for mechanical...
TRANSCRIPT
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QA of Hydroacoustic Instruments
What's My Responsibility?
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Overview of Presentation
Hydroacoustic Instruments – Discharge measurements and Index Velocity
Instrument Quality Assurance
Acceptance Testing [HIF + WSC]
Post Factory-Repair Testing [HIF and(or) WSC]
Routine QA [WSC]
QA for Instruments for which formal testing by OSW is incomplete [WSC]
ADVM QA
Question and Answer
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Why do we Care about QA?
Many procedures exist for mechanical current meters (spin tests, checking pivots/bucket wheels/yokes, current meter exchange, etc.)
Need have equivalent practices for acoustic instruments
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1995 2006 2007 2008 2009 2010
Perc
en
t
Percent of Discharge Measurements Made with Hydroacoustic Instruments
Approximately 6% of streamflow stations
are index velocity stations
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What’s My (Your) Responsibility?
Objective of this presentation:
Create awareness of QA activities and their importance
Provide overview of QA activities led by OSW and others
Focus on QA activities you can influence or control for hydroacoustic instruments used to make discharge measurements
Brief overview of ADVM QA
QA is EVERYONE’s responsibility! (i.e. not just OSW)
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Hydroacoustics Instruments
Discharge Measurement Instruments
Tested by OSW with formal policy/guidance
Incomplete testing with no formal policy/guidance
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Hydroacoustics Instruments
Acoustic Doppler Velocity Meters
Index velocity instruments
Instrument and measurement QA are closely linked
Details require a separate webinar
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Three Kinds of Testing
Acceptance Testing [HIF + WSC]
Testing conducted to determine if basic requirements instrument operation are met
Example: Staff sections are tested to verify that the distance indicated on the staff is accurate to within some spec
Post Factory-Repair Testing [HIF + WSC]
Testing conducted after a repair. May include all or part of acceptance test procedures
Routine QA [WSC]
Routine tests done to assure user that instrument is functionally normally
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Advantage of HIF Purchase
Acceptance testing: 100% of Flowtrackers / ADCPs purchased through the HIF are tested
HIF coordinates recalls/updates, etc.
HIF maintains database with info on every Flowtracker purchased/repaired/tested
Lower overhead means lower cost for WSCs
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HIF Acceptance Testing - Flowtrackers
Power-up check
Thermistor test
Beam Check
Automated tow tank test
Two cart speeds 18 & 33.5 cm/s
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WSC Acceptance Testing - Flowtrackers
Check Flowtracker operation
Refresh batteries if necessary
Power up and check menus
Perform a bucket test
Best Practice: Perform a check discharge measurement to verify that the Flowtracker is working. Compare to expected discharge (rating or shifted discharge) provided it is relatively accurate. Doesn’t have to be a comparison to AA or ADCP
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HIF Acceptance Testing - ADCPs
Tests consist of:
Power-up check: comms, heading, pitch/roll, ping
Thermistor validation
Distance test in flume – StreamPro and M9/S5s only
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HIF Acceptance Testing - ADCPs
New ADCP testing tank being constructed
Dimensions: 80 x 4 x 4 ft.
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WSC Acceptance Testing - ADCPs
System checkout
Apply power
Check comms
Run diagnostic tests
Note transformation matrix – TRDI ADCPs
Best Practice: Perform at least 1 check measurement to verify that the ADCP is working. Compare to expected discharge (rating or shifted discharge). Comparison doesn’t have to be with AA, Flowtracker, or ADCP. >PS3
1.4789 -1.4747 -0.0082 0.0035
-0.0222 0.0269 -1.4724 1.4705
0.2673 0.2643 0.2702 0.2612
1.0391 1.0453 -1.0403 -1.0451
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Post Factory Repair Testing - Flowtrackers
Must be returned to HIF after factory repairs – regardless of who (HIF or WSC) initiated the repair
Best Practice: Arrange for repairs via HIF
When received by HIF they will:
Verify to the extent possible that repair was successful
Perform routine acceptance tests
When received at WSC, hydrographer:
Should conduct power-up testing and bucket test
Best Practice: Make a check QM
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Post Factory Repair Testing - ADCPs
Not required that ADCP be returned to HIF – though HIF can assist with this
WSC staff should perform system checkout
Apply power
Check communications (BBTalk)
Run diagnostic tests
Check values of transformation matrix and compare to values prior to repair (should be the same)
Best Practice: Make a check QM to verify that ADCP is functioning normally. Not required.
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Routine ADCP QA – Beam Alignment
Testing all aspects of an ADCP is almost impossible under any circumstances. Beam alignment errors are potentially the largest source of BIAS
30
40
V*Sin (40) V*0.64
V*sin (30) V*0.5
V
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Routine ADCP QA – Beam Alignment
OSW Technical Memo 2009.05 states that beam alignment test should be done for
All new instruments not tested by HIF
Any ADCP returned from factory repair or evaluation
Every instrument once every 3 years
After firmware upgrades (?)
Checking that transformation matrix is unchanged is probably sufficient after a firmware upgrade. Make sure to store a log of matrix.
>PS3
1.4789 -1.4747 -0.0082 0.0035
-0.0222 0.0269 -1.4724 1.4705
0.2673 0.2643 0.2702 0.2612
1.0391 1.0453 -1.0403 -1.0451
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Routine ADCP QA – Beam Alignment Requires:
Manned boat with ADCP/GPS mounts
GPS with differential capability (WAAS) (GGA & VTG)
Lake or water body shallow enough to reliably bottom track with no rapid changes in bed elevation
Ability to navigate at constant heading & speed for long distance
Considerations:
Test does not evaluate water tracking, though beam alignment affects both BT and WT
Need to maintain bottom tracking
Heading is important – NOT course!
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Mount ADCP (note beam orientation)
Conduct internal ADCP diagnostic tests
Begin pinging – but not recording
Configure software to view Distance Made Good (DMG) and ratio of BT and GPS DMG (known as BC/GC)
Record GPS (GGA/VTG) and ADCP data
When boat at desired speed, begin recording
Maintain constant compass heading /speed
Beam Alignment Procedure
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Beam Alignment Procedure Traverse a long (1,200–2,500
ft) course. Longer is better
At the end of the course but before reducing speed or changing heading, stop recording
Record BC/GC value
Do a reciprocal traverse (a transect of the same length at a heading ~180 degrees from the previous course)
Bad
Good
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Beam Alignment Procedure
Record BC/GC value
Average BC/GC values for reciprocal courses
Rotate ADCP 45 degrees and repeat 4 times
For most ADCPs: 0.995 < BC/GC < 1.003
If BC/GC is outside this range, arrange for return to factory for factory beam alignment test
Alternative: Pay for factory to perform test and report results
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Beam Alignment Procedure
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Beam Alignment Procedure
Document and store results in accordance with QA plan / Electronic data archive. Preferably use an Instrument History Log
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Routine ADCP QA – Beam Alignment
Instrument-specific Considerations
M9/S5s: Similar performance to Rio Grande? Can ask HIF to perform distance test for a fee
StreamPros: Cannot be tested without compass & GPS. HIF/Mfgr can conduct beam alignment test.
RiverRay ???
Policy/experience with new instruments will evolve. Makes comparison QMs are all the more important.
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Routine QA - Flowtrackers
Review auto-beam checks for every QM
Document any changes/anomalies
Run bucket test if QC Check fails
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Routine QA - Flowtrackers
Bucket tests
After questionable results on auto-beam check
After possible damage to instrument (a drop, etc.)
Log and compare with previous log tests – should be consistent over time
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Routine QA - Flowtrackers
Flowtracker Calibration Program
Every ADV recalled every 3 years (OSW Memo 2010.12)
Tests performed include: thermistor check, bucket test, and tow tank test at 2 speeds
Flowtracker re-calibrated if necessary
A WSC may request that a Flowtracker be tested at any time
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Routine QA - Flowtrackers
OSW Flowtracker Calibration Program - Hydrographer Responsbilities:
Register all WSC Flowtrackers in HIF database
(http://1stop.usgs.gov/flowtracker/)
Respond in a timely manner to recall or let HIF know
Review results (ask questions as necessary)
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Routine QA - Flowtrackers
Sample Flowtracker QA Test Results
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FlowTracker QA Test Results
23 meters (~9%) failed at least 1 of the QA tests
Temperature probe failures: 4 (~2%)
Velocity failures: 11 (~4%)
Remainder: beam check
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Periodic Instrument Check
Best Practice: Conduct periodic instrument checks. Not required. Conduct at regular interval, e.g. annually?
Individual ADCP comparison QMs
Compare discharge measured with your ADCP with discharge measured with a current meter, some other accepted instrument, or stable S-Q rating
Don’t always use the same measurement location
What happens when the comparison is outside an acceptable range (for example 5%)? Repeat measurements – also at different sites
Record results in Instrument History Log
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Periodic Instrument Check
ADCP Regattas
Compare discharges measured by many/all WSC ADCPs
Select site where multiple sections can be used
Ideally have one instrument measuring continuously
Steady – or near steady-flow conditions
Synchronize times for ADCPs/Laptops before starting
Maintain 5 channel depth separation for similar acoustic frequencies
Good opportunity for review of important policies, new info regarding ADCPs, etc.
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Example Regatta Summary http://hydroacoustics.usgs.gov/publications/CA-ADCP-Check-2007.pdf
2000
2200
2400
2600
2800
3000
8:00 AM 9:00 AM 10:00 AM 11:00 AM 12:00 PM 1:00 PM 2:00 PM 3:00 PM 4:00 PM
ADCP Comparison Data June 22, 2010
(each point represents a 4 transect mean)
Baseline (OSW 1406 / 600 kHz) IL 9521 (1200 kHz)IL 8630 (1200 kHz) IL 8619 (600 kHz)IL 8589 (1200 kHz) IL 8570 (600 kHz)IL 6223 (1200 kHz) IL 6222 (1200 kHz)
Time
Dis
charg
e (c
fs)
IL WSC 2010 Regatta
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New Profilers
M9
S5
SonTek/YSI RiverSurveyor TRDI RiverRay
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New Instruments: RiverSurveyor and RiverRay
OSW doesn’t have sufficient data to find all potential issues
Make comparison QMs for the range of conditions Water velocities
Streambed type
Flow depths
Turbulence
Sediment concentration
Use the instrument if there are no significant differences from the comparison measurements. Consistent biases are of particular concern
Document and submit comparisons to OSW Sharepoint site https://xcollaboration.usgs.gov/wg/OSWHA/Testing
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Sharepoint Testing Pages
https://xcollaboration.usgs.gov/wg/OSWHA/Testing
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Sharepoint Testing Pages
https://xcollaboration.usgs.gov/wg/OSWHA/Testing
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Ott ADC Make comparison QMs for the range of conditions
Water velocities
Streambed type
Flow depths
Turbulence
Sediment concentration
Use the instrument if there are no significant differences from the comparison measurements. Consistent biases are of particular concern
Ott ADC
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ADVM QA
Independent water temperature checks every site visit (at depth of & near to ADVM transducers)
Monitor time series data for changes (SNR, temperature, velocities, pitch/roll, standard error, cell end, water depth, etc.)
Water Temperature
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ADVM QA
Cell End
Heading, Pitch, and Roll
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ADVM QA
Range-averaged Velocity
Multi-cell Velocities
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ADVM QA
SNR
Pressure & Water Depth
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Questions?